Power operated typewriter



April 21, 1964 J. F. HEYER 3,129,801

POWER OPERATED TYPEWRITER Filed May 1, 1962 IN V EN TOR.

13 5% Y John F. Heyer AGENT United States Patent 3,129,831 PGWER()FERATED TYPEWRITER .lohn F. Heyer, West Hartford, 1101111., assignorto Underwood Corporation, New York, N.Y., a corporation of DelawareFiled May 1, 1952, Ser. No. 191,595 7 iliairns. ((31. 197-17) Thisinvention relates to typewriters in general and more particularly to thekind in which type actions are selectively associable with a commonpower drive member for receipt of transitory power impulses, and whereinas a result the type bars are driven partially toward a printing pointbut complete their printing motion by power to momentum.

Such typewriters embody conventionally devices where by within certainlimits the intensity or magnitude of the power impulses impartable tothe individual type actions are predeterminable in respect thereto.Certain type actions, such as those for typing punctuation marks, embodytypes of very small printing areas. These type actions relatively toothers should give forth very light printing blows if they are toproduce imprints of substantially the same darkness or texture as thelarge type-face actions, or if they are to avoid perforating the worksheet.

It has been extremely difiicult in the past, and often totallyimpractical, to adjust the power impulses of the punctuation typeactions or obtain with reasonable constancy and accuracy the desiredweakness of impressions. The underlying main reason for this has beenthat weakpowered impressions required very short power pulses which areunreliable to control, and also call for unduly long momentum travels ofthe type bars wherein the latter are subject to unpredictable frictionconditions. Moreover, the degree of effectiveness of the power impulsesof short durations on the type bars were very greatly affected by themomentary conditions under which the type actions happened to be pickedup. If a type action happened to be picked up from full rest, then theeffective power impulse imparted thereto obviously was greatly differentthan if the action was picked up while returning from a previousoperation. If power impulses are very short, then also other mechanismshocks are unduly conducive to non-uniformity of typing performance.

According to the present invention, at least certain type actions whichembody types of very small printing areas, such as the punctuation typeactions are provided with flexible motion transmitting provisions whichare so constituted that such type actions, when power pulsed, willsustain a loss of energy transmittal to the type bars, causing them totype with diminished vigor. The said provisions are preferably of acharacter so that the stated loss of energy transmittal is so great asto make longer power pulses necessary which will enable the type actionsto perform with better control and uniformity. The type bars having thestated flexible motion transmitting provisions associated therewith arepower-moved closer to the platen but attain a lesser speed andconsequently strike with lesser but better controlled speed.

Resilient provisions in the type bar operating trains are known in theart but not organized in a cooperative relationship which produces theaforestated results and advantages.

It may thus be stated to be a broad and general object of the inventionto provide in a power-operated typewriter, simple and efiicient meansfor obtaining typing impressions of uniform-strength appearance from allthe various type-actions, regardless of type areas involved.

It is also an object of the invention to provide for transmittal ofpower operating strokes at least in connection with certain type barswith an attendant loss of energy transmittal thereto, thereby to providefor weakened typing impressions calling for longer and bettercontrollable power actuating impulses.

It is a still further object of the invention to provide efficient poweroperating means for type actions correlatedly with power regulatingmeans therefor so that despite the diifering-area printing faces on thetype bars, appropriately proportioned power movements will be impartedto all type bars to produce substantially equal strength appearanceimprints at each different regulated position of said means.

Other objects of the invention will become apparent upon considerationof the drawings and in the light of the description which follows.

In said drawings:

FIGURE 1 is a sectional side elevation showing in its normal position apower-operable type action embodying a flexible motion transmittinglink,

FIGURE 2 is a side elevation similar to FIGURE 1, but illustrates thetype action partially operated and sustaining a loss of energytransmittal to the type bar,

FIGURE 3 is an enlarged-scale detail view of said flexible motiontransmitting link in a strained condition,

FIGURE 4 is an enlarged-scale detail view of a nonfiexible motiontransmitting link, and

Finally, FfGURE 5 is a cross-sectional detail View of the flexible linkof FIGURE 3 at line 55 of such figure.

The invention is disclosed in connection with a power type action of thekind shown in the patent to Yaeger, No. 2,675,109, dated April 13, 1954.Referring now to FIGURE 1, type bars 19 are arranged in a usual curvedarray for pivotal movement against a platen 11 from diversive positionsin which they rest on a usual curved pad 12. A single power roll orfluted shaft 13 is common to all the type bars 10. It extendstransversally of the machine and is driven in the direction of theindicated arrow. A series of power actuators 14 which are individuallyrelated to the various type bars, stand normally all disengaged from thefluted shaft 13 thereabove in the position seen in FIGURE 1, eachactuator including a usual snatch pawl 15 pivotally carried thereon.

At their front ends, the actuators 14 are pivotally connected to arms 17which are provided on a frame supported pivot rod 18. Each actuator 14has a spring 20 urging it rearwardly and upwardly to the normal positionseen in FIGURE 1, the normal position of separation of the snatch pawl15 from the fluted shaft 13 being established in cooperation with a bar21.

Engagement of said actuators is selectively e'ifectable under thecontrol of type keys, not shown, or otherwise, through the operation ofhook elements 16 which overlie lugs 19.

Each arm 17 operates a related sub-lever 22 by contact with a rollingface 23 on the latter. Said levers 22 reach upwardly to the differinglevels of the related type bars, and, according to a preferred form ofthe invention, some are connected to their type bars by a flexiblyextendable link structure 25, and some by a plain link 26 of constantlength. Said flexibly extendable link structures 25 are provided only inassociation with the type bars which have type faces of very smallprinting area, such as the punctuation type bars. A link structure 25 isshown in FIGURE 3 in an enlarged and extended aspect. It comprises twolink elements 27 consisting of stiff wire stock in a straight line, suchelements having thereon a spring coil 29 which by reduced-diameter ends30 has opposite anchorage association with said elements 27 at spacedlocations. Intermediate said coil ends 30, the spring coil is slightlylarger for the link elements 27 to slide therein freely, but snugly.Moreover, the link elements 27 have Within the spring coil, portions 31of half-round cross section which are slidingly adjacent, the springcoil 29 being efiective to maintain the link elements 27 slidingly andfairly stifliy in line. A preferred manner in anchorage of the springcoil 29 on the elements 27 will be described in detail later herein. Thespring coil 29 constitutes a flexibly strainable motion transmittingelement in a type bar actuating train.

The contracted, normal condition of the link structures 25 is depictedin FIGURE 1. A spring 32 biases each sub-lever 22 and related type barto its normal position as illustrated in FIGURE 1. The rolling faces 23are preferably designed so that the differently located upper ends ofthe sub-levers 22 have substantially the same accelerationcharacteristics.

Upon engagement of any actuator 14, it will be driven forwardly toimpart a cyclic motion to its related sublever 22. At a predeterminedpoint the actuator, while being driven, engages by a cam face thereof anadjustable abutment 34- which is individual thereto, these abutmentsbeing provided on a transverse bar 35, Consequential to suchengagements, as illustrated in FIGURE 2 the actuators 14 disengagesthemselves from the fluted shaft. In type actions which embody theconstant-length links 26, the type bars iii are forcibly driven untilthe disengagement of the actuator 14 occurs. However, in reference tothe type actions which embody a flexibly extendable link 25 the strengthof the spring coil 2& is such that, as shown in FIGURE 2, it willundergo considerable yielding While transmitting motion. This means thata loss of mot-ion transmittal to the type bar occurs by reason of theflexible nature of the link structure 25. It further means that some ofthe energy input by the actuator 14 is not transmitted to the type barIt).

In FIGURE 2, the actuator 14 is shown at the point of disengagement. Inview of the flexible nature of the link structure 25, the full lineposit-ion of the type bar 10* has been reached. Had the link 25 beeninflexible, then the type bar 10' would have reached the positionindicated at Obviously the amount of energy transmittal over theindividual link structures 25 is variably predeterminable by adjustmentsof the abutments 34-.

As soon as the actuator 14 becomes disengaged, the energy stored in thestrained spring coil 29 becomes unavailable for further drivinginfluence on the type bar because the sublever 22 is then free torestore and will do so under the tension of its spring 32. The loss ofenergy transmittal provided for in the above manner is very appreciableand has facilitated a considerable lengthening of the power stroke ofthe actuators 14 in all those type actions that are equipped with theflexible link structure 25, it being understood that the loss oftransmitted energy is evidenced by a reduced speed of travel of thepertinent type bar. The lengthening of the power strokes as facilitatedby the link structure 25 has also the beneficial effect that at the timethe actuator disengagement takes place, the mechanism shocks, which areincidental to the initial pick up of the type actions and of differingviolence, are already well absorbed, that is the type bar travels thenat well-controlled speed. On the other hand the increased distance oftravel of the type bars 10 effected under the power of the actuators 14provides that the type bars are required to move under momentum a lesserdistance, so that frictional influences, which are subject to change,are encountered over a shorter range of type bar travel, and thus becomeminimized.

Collective regulation of strengths of imprints is obtainable throughadjustment of the abutment bar 35, by old mechanism. Said bar 35 forms apivoted bail structure with spaced levers 37 so that this bail structureis differently positionable by an impression regulating control knob 38,through cams 39.

With respect to type actions embodying extendable link structures 25,the adjustment of the bar 35 for lengthened strokes of the actuators 14has the effect of causing increased straining of the link structureswith an attendant greater loss of energy transmittal to the type bars.This loss of energy attendant in respect to type bars which are operatedby extendable link structures 25 is so proportioned that in the variouspositions of the impression control all the type bars will effectimprints of substantially uniform imprint-strength appearance despitethe printing faces of greatly diflering areas.

The reduced-diameter ends 30 of the spring coil have a press tit uponthe link elements 27. However, the frictional grip afforded isinsufficient to maintain the spring coil ends firmly anchored. In fact,each time the link structure 25 is strained, the coil ends 30 will slipa minute extent on the elements 27. Then, Whenever the structure 25contracts following its straining, the link elements 27 snap in oppositedirections toward each other so that the instance the spring coilbecomes fully contracted, the spring ends 3% tend to execute a violentjump from each other beyond their original positions on the linkelements 27. For controlling such jumps of the spring ends 39', the linkelements 27 are each provided with two diametricaily opposite undercutburrs 40. Through said burrs ill, the spring ends 30 become relocated incorrect relations on the elements, each time cancelling out the slippagewhich occurs as the spring 29 is strained. It will be observed that theburrs do not serve as anchorages. Also to be noted is that the linkstructures 25 are very slender, which is important in view of the dangerof operating interference between them. Instead of the springs 39 havingfrictional association upon the link elements, their ends may beattached otherwise, as by soldering. However, this method of attachmentis expensive and has been found to be subject to failure after long-timeuse.

According to the preferred embodiment of the invention hereinabovedescribed, the flexibly extend-able link structures are restricted totype bars 10 having small-face types. It has however been discoveredthat the flexibly extendable link structures may be advantageously usedadditionally in type actions embodying large-face types. Obviously ineither of these different embodiments of the invention the type actionswith increasingly larger face types require correspondingly increasedstronger typing blows against the platen. If the flexibly extendablelink structures are also to be used for large-face type actions, thenreduced lengths of power strokes for some of the very large-face typeactions are in order. This is because the pertinent link structures areundergoing recovery toward normal length before the actuatordisengagement takes place so that consequently the type bar speed issuper-imposingly increased by the recovery of the spring coil 29 beforethe actuator disengages. The link structures 25 or equivalent flexiblemotion transmitting provisions have the advantageous effect ofcushioning undue mechanism shocks and particularly also the shocks whichaccompany the disengagement of the actuators. it is for this reasonespecially that type actions involving relatively large type-faces maybe equipped also with flexible motion transmitting provisions, but, ofcourse, these provisions do not act to divert printing energy from therelated type bars.

It should be understood that broadly the invention provides for a lossof energy transmittal to at least one type bar, through the provision ofany kind of flexible motion transmitting provision in its operatingtrain which strains but does not recover substantially before the poweroperating pulse ceases.

The spring coil 29 in any type action may be said to constitute aflexibly strainable motion transmitting element which has a flexingstrength properly correlated on one hand to the power stroke force ofits related actuator and on the other hand also to the inherent force ofopposition to acceleration aflorded by the type bar, so that the powerstroke of said actuator produces through such strainable element 29 apartial power operation of the type bar and attendant thereto producesin said element itself a flexure which obtains at the end of saidpartial power operation. Obviously, when in the cyclic operation of theactuator 14 the latter becomes divorced from the constantly operatingpower member 13, there results immediately a relaxation of the thenflexed element 29. Therefor, the energy which as a result of the saidpartial power operation of the type bar has become stored in saidelement 29, becomes promptly and automatically unavailable for type bardriving influence, so that thereupon the completing operation of thetype bar is by force of attained momentum and devoid of that part of theenergy which produced the flexure of said element 29.

What is claimed is:

1. A spring link motion transmitting assembly comprising in combination,

(a) two wire rods extending toward each other in a straight line andincluding portions of generally complemental fractional cross sectionextending in a lengthwise overlapping relationship and slidably parallelto each other,

(b) and a distensible spring coil being placed axially parallel uponsaid wire rods with at least said overlapping rod portions slidably andstiflly contained therein and with the spring coil at opposite locationsbeyond said rod portions having impositive anchoring attachment on saidrods through some end-turns thereon having a diametrically contractingfriction hold thereon,

(c) the said rods embodying abutment means for said spring coil by itsends to locate oppositely thereagainst through shock movements of thespring coil ends lengthwise from each other when the spring coil turnscompact against each other after the spring link assembly hastransmitted motion.

2. In a typewriter, the combination of:

(a) a type bar,

(b) a constantly operating power member,

(0) and means to transmit motion from said power member to said type barto drive the latter partially toward a printing position, comprising,

(d) an element for motion-receiving association with said power memberfor a given period to receive a given-extent power motion therefrom,

(e) and comprising further a flexible motion transmitting link structurewhich is so constituted that attendant to transmitting motion it willbecome extended to a significant degree from a normal condition and sothat at the end of said motion receiving association of said element thetype bar will be travelling at a lesser speed than if said provisionwere inflexible, said provision after said limited motion receivingassociation of said element, being allowed by the latter to resume itsnormal condition without exerting further driving force on said typebar, the said link structure comprising,

(f) two elongate elements extending toward each other in line,

(g) a distensible spring coil placed over said elongate elements andhaving coil-ends forcibly pressing thereupon to have friction holdsoppositely thereon at two spaced points but said elongate elementshaving free sliding capability intermediately of the coil ends, saidspring coil being normally contracted substantially to compactness,

(h) and abutment means on said elongate elements and adjoining the saidcoil ends therebeyond for location of the latter thereagainst,

(1) each of said coil-ends having friction holds on said elements whichmay slip slightly therealong from said abutment means when the springcoil is being distended, said spring coil by contracting to compactnessfollowing each operation of said element, moving said elongate elementsrelatively toward each other and the shock of completely effectedcontraction of said spring coil, urging said coil-ends from each otherso as to locate them on the element to the opposite limits afforded bysaid abutments, wherefor the spring coil-ends are correctly correlatedin respect to the elongate elements after each effected type baroperation.

3. In a typewriter having a type bar, a flexibly extendable linkstructure for transmittal of motion to said type bar comprising:

(a) two elongate link-elements in line,

(b) a distensible spring coil placed over said elongate elements andhaving coil-ends pressing forcibly at two spaced points thereupon toexert friction holds thereon but said spring coil intermediate of saidcoil-ends being dimensioned relatively to said elements for slidingcapacity thereon,

(c) and abutment means on said elements and adjoining the said coil-endstherebeyond for location of the latter thereagainst, each of saidcoil-ends having friction holds on said elements which may sliptherealong slightly from said abutment means when the spring coil isbeing distended, said spring coil, when contracting subsequently tobeing distended, moving said elements relatively toward each other sothat when said spring coil becomes fully compacted, the coil-ends willreceive shocks directionally from each other, inducing them to slipreversely on said elements to the limit afforded by said abutments.

4. The invention set forth in claim 3, the said elements being made ofround stock and said abutments being struck up from said round stock toproject radially therefrom.

5. In a typewriter having a type bar and power means to operate saidtype bar, in combination:

(a) a constantly operating power member,

(b) a type bar actuating train interposed between said member and saidtype bar and comprising therein,

(b1) an actuator connectable transitorily with said member for receiptof a cyclic power stroke therefrom wherein said train operates said typebar only partially toward a printing position (b2) and a flexiblystrainable motion transmitting element of a flexing strength socorrelated on one hand to the power stroke force of said actuator and onthe other hand to the inherent force of opposition to accelerationafforded by said type bar, that the power stroke of said actuatorproduces through said element a partial power operation of said type barand attendant thereto produces in said element itself a flexure whichobtains at the end of said partial power operation,

(0) means to connect said actuator with said member for receipt of saidcyclic power stroke,

(cl) and means associated with said actuating train to facilitate at theend of said partial power operation of said type bar an immediaterelaxation of the then flexed element and consequently to facilitate acompleting travel of the type bar by force of attained momentum which isdevoid of that part of the operating energy which was instrumental toproduce the fiexure of said element.

6. The invention set forth in claim 5, the said flexibly strainablemotion transmitting element comprising:

(a) two wire rods extending toward each other in a straight line andincluding portions of complemental fractional cross sections extendingin a lengthwise overlapping parallel relationship,

(17) and a distensible spring coil carried axially parallel upon saidwire rods and having an interior diameter to confine said overlappingrod portions mutually therein in a stiffly but freely telescopingmanner, said spring coil having at its opposite ends anchorageassoications upon the two wire rods which extend toward each other.

7. In a typewriter having a complement of type bars large printing facearea types and having power means to operate said type bars, incombination:

(a) a constantly operating power member, (12) individual actuatingtrains for said type bars inter- (c) the typewriter including further,selective control means to connect said elements for recipt of saidcyclic power strokes,

(d) and means variously associated with said actualsa posed between saidpower member and the various tors to disconnect them from said powermember type bars and comprising each, after receipt of their said poweroperations, whereby (bl) an actuator connectable transitorily with saidat the end of the stated power operation of any type member forreceipt'of a cyclic power stroke therebar embodying in its train aflexibly strainable elefrom to effect an operation of the related typebar ment, there is facilitated the immediate relaxation partially towarda printing position. of such element and thus a completing movement of(b2) the actuating trains related to such of the type the operated typebar by power of momentum which bars which have relatively small printingface area is devoid of the part of energy input expended by types,exclusive of those related to such of the type the actuator in effectingthe flexure of said element. bars which W relatively laige printing facei References Cited in the file of this patent types, comprising each aflexibly stramable motion 15 transmitting element of a flexing strengthcorrelated UNITED STATES PATENTS on one hand to the power stroke forceof its related 394,607 Perry Dec. 18, 1888 actuator and on the otherhand to the inherent force 694,015 Hess Feb. 25, 1902 of opposition toacceleration afiorded by the type 704,869 Fischer etal July 15, 1902 barrelated thereto, so that the power stroke of any 776,103 B rron No 29,1904 of these actuators through its related strainaole ele- 884,735Howell Apr. 14, 1908 ment produces a partial power operation of the type1,037,339 Secor Sept. 3, 1912 bar in train therewith and attendantthereto produces 2,675,109 Yaeger Apr. 13, 1954 in said element aflexure which obtains at the end 2,871,612 Mohn Feb. 3, 1959 of suchpartial power operation, 2,894,613 Ayres July 14, 1959

1. A SPRING LINK MOTION TRANSMITTING ASSEMBLY COMPRISING IN COMBINATION,(A) TWO WIRE RODS EXTENDING TOWARD EACH OTHER IN A STRAIGHT LINE ANDINCLUDING PORTIONS OF GENERALLY COMPLEMENTAL FRACTIONAL CROSS SECTIONEXTENDING IN A LENGTHWISE OVERLAPPING RELATIONSHIP AND SLIDABLY PARALLELTO EACH OTHER, (B) AND A DISTENSIBLE SPRING COIL BEING PLACED AXIALLYPARALLEL UPON SAID WIRE RODS WITH AT LEAST SAID OVERLAPPING ROD PORTIONSSLIDABLY AND STIFFLY CONTAINED THEREIN AND WITH THE SPRING COIL ATOPPOSITE LOCATIONS BEYOND SAID ROD PORTIONS HAVING IMPOSITIVE ANCHORINGATTACHMENT ON SAID RODS THROUGH SOME END-TURNS THEREON HAVING ADIAMETRICALLY CONTRACTING FRICTION HOLD THEREON, (C) THE SAID RODSEMBODYING ABUTMENT MEANS FOR SAID SPRING COIL BY ITS ENDS TO LOCATEOPPOSITELY THEREAGAINST THROUGH SHOCK MOVEMENTS OF THE SPRING COIL ENDSLENGTHWISE FROM EACH OTHER WHEN THE SPRING COIL TURNS COMPACT AGAINSTEACH OTHER AFTER THE SPRING LINK ASSEMBLY HAS TRANSMITTED MOTION.